Computer networks ppt by Shivam Sharma.pdf

1. Multiplexing
Many to one/one to many
Types of multiplexing

2. Multiplexing
It is the set of techniques that allows the
simultaneous transmission of multiple signals
across a single data link.
Multiplexing is done using a device called
Multiplexer (MUX) that combine n input lines
to generate one output line i.e. (many to one).
At the receiving end a device called
Demultiplexer (DEMUX) is used that separate
signal into its component signals i.e. one input
and several outputs (one to many).

3. Multiplexing…

4. Advantages of Multiplexing
More than one signals can be sent over single
medium or link
Effective use of the bandwidth of medium

5. Multiplexing vs. No Multiplexing

6. Types of Multiplexing
Synchronous TDM Asynchronous TDM

7. Frequency Division Multiplexing
It is an analog technique.
Signals of different frequencies are combined
into a composite signal and is transmitted on
the single link.
Bandwidth of a link should be greater than the
combined bandwidths of the various channels.
Each signal is having different frequency.
Channels are separated by the strips of unused
bandwidth called Guard Bands (to prevent
overlapping).

8. FDM

9. Applications of FDM
FDM is used for FM & AM radio broadcasting.
AM frequency = 530 to 1700 kHz.
FM frequency = 88 to 108 MHz.
FDM is used in television broadcasting.
First generation cellular telephone also uses FDM.

10. FDM, Time Domain

11. Multiplexing, Frequency Domain

12. Demultiplexing, Time Domain

13. Demultiplexing, Frequency Domain

14. Wave Division Multiplexing
WDM is an analog multiplexing technique.
Working is same as FDM.
In WDM different signals are optical or light signals that
are transmitted through optical fiber.
Various light waves from different sources are combined to
form a composite light signal that is transmitted across the
channel to the receiver.
At the receiver side, this composite light signal is broken
into different light waves by Demultiplexer.
This Combining and the Splitting of light waves is done by
using a PRISM. Prism bends beam of light based on the
angle of incidence and the frequency of light wave.

15. Wave Division Multiplexing…

16. Time Division Multiplexing
It is the digital multiplexing technique.
Channel/Link is not divided on the basis of
frequency but on the basis of time.
Total time available in the channel is divided
between several users.
Each user is allotted a particular time interval
called time slot or slice.
In TDM the data rate capacity of the
transmission medium should be greater than
the data rate required by sending of receiving
devices.

17. TDM